Sea lamprey to be trapped in several 3 local rivers

Adult sea lampreys from the Pigeon, Sturgeon and Maple rivers will be trapped from April until late June to help determine the population size and more.

By Shawna Jankoviakshawna@cheboygantribune.com

Adult sea lampreys from the Pigeon, Sturgeon and Maple rivers will be trapped from April until late June to help determine the population size and more.Nets could be set late next week, after more snowmelt has flushed through the system. According to Research Ecologist and Project Leader Nicholas Johnson of the U.S. Geological Survey, the trapping is part of an effort to control invasive sea lamprey in the Cheboygan River in order to maintain its health and that of Lakes Huron and Michigan.“The sea lamprey trap at the dam in Cheboygan captures more adult sea lampreys than any other trap in the Great Lakes,” according to Johnson. “Despite having an efficient trap and refurbished dam, the upper river (upstream of lock and dam) remains infested with sea lampreys and has been treated with lampricides on a 3-year cycle for nearly 50 years at an average treatment cost of $500,000 per treatment.”Johnson said it is believed that sea lampreys are escaping through a navigational lock near the dam to infest the upper river. However, a 2011 telemetry study showed the percentage of lampreys escaping through the lock was lower than expected.“An alternative reason as to why the upper river supports a robust sea lamprey population is that sea lamprey in the upper river complete their life cycle in Burt and Mullet Lakes without entering Lake Huron (landlocked),” Johnson said. “This explanation has been supported by capture of sea lampreys attached to fish in Burt and Mullet Lakes. If a landlocked population resides in the upper river, plans to eradicate sea lampreys from the upper river must be formulated prior to rebuilding the lock (a project currently being explored). Otherwise, continued lampricide treatments in the upper river would be necessary and money spent on refurbishing the lock to block sea lamprey migration would have been wasted.”The trapping project will determine if a landlocked population of sea lamprey exists in the upper river. Data from those lampreys will be compared to lampreys captured in the lower Cheboygan River at the dam.“If a landlocked population exists, we predict that adult sea lampreys would be captured in the upper river before lock operation begins, adult abundance would be greater than predicted if escapement through the lock was the only source of adults, and statolith microchemistry and morphology of adults captured in the upper river would differ from those in the lower river,” Johnson said.The mark-recapture survey will be conducted in each stream to estimate sea lamprey abundance by releasing fin-clipped lampreys downstream of the netting location to estimate trap efficiency. In the Pigeon River, sea lamprey will be trapped at Afton Road and will be released at the East Mullett Lake Road bridge. In the Sturgeon River, sea lamprey will be trapped at Hoakwood State Park and will be released at the M-68 crossing behind McDonald’s. In the Maple River, sea lamprey will be trapped at Maple River Road and will be released at Brutus Road.